I just installed Ubuntu, a full install removing the prior OS. I was forced to remove Windows 7 from my HP dv6 because of the max four partitions already being there. I didn't lose anything, all backed up. However, now I am looking to create another partition and install Windows 7 on it.

Do I also need some sort of boot loader that lets me choose which to boot?

6 Answers
6

Boot the Windows 7 disk and install it on the partition created in the previous step. (Windows will not provide you with the option of choosing Ubuntu). So Ubuntu would seem unusable.

Recover Ubuntu by using a live CD (or live USB) and following the steps mentioned in Ask Ubuntu question Recovering GRUB after installing Windows 7 (at the end, you should have the option of choosing the operating system from the GRUB menu.)

It's easy to install dual OS, but if you install Windows after Ubuntu, Grub will be affected. Grub is a boot-loader for Linux base systems. You can follow the above steps or you can do just the following:

Make space for your Windows from Ubuntu. (Use Disk Utility tools from ubuntu)

GRUB will let you boot into both OS's but installing Windows 7 after Ubuntu will remove GRUB from MBR, so you'll have to reinstall GRUB. Install Windows 7 on any partition of your choice and than follow this link to repair the GRUB. Unable to load Ubuntu after installing Windows

Delete a partition from your current setup that refers to swap area, or linux swap. You'll be able to re-create and tune it later. Create a logical partition in place of the removed one. From now on, you'll be able to create more logical partitions. Fill the created partition with you Win-7 backup (if you don't have enough space for it, resize other partitions to free some space beforehand). Then boot Linux and do update-grub, that will detect your Win-7 partition and will put a line for booting to it in the boot menu. Then reboot into your system of choice - you're dual-booter now!